For example, there is a radio control system that controls the brightness of a luminaire using a remote operation device. In such a radio control system, a one-way system for transmission from the remote operation device to the luminaire is used as a simple configuration. Therefore, the remote operation device needs to store an operation state of the system in order to display the operation state of the system. In general, since the remote operation device operates with battery power, power consumption is limited. Therefore, it is likely that an operation state stored in the remote operation device and an actual operation state of the luminaire are different because of a communication error or the like.